Rheostat.



L. L. TATUM.

RHEOSTAT APPLICATION FILED FEB.21.19I5.

Patented Nov. T, 1916.

UNITED sTATEs PATENT oEEIoE.-

LEWIS L. TATUM, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMER MFG. CO., OF MILWAUKEE, WISCONSIN, A CORPORATION 0F WISCONSIN. I

RHEOSTAT.

Specification of Letters Patent.

Patented Nov. 7, 1916.

Application led February 21, 1916. Serial No. 79,663.

To all whom t may concern:

Be it known that I, LEwrs L. TATUM, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Rheostats, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to rheostats and is particularly applicable to drum controllers of that type wherein a field rheostat is provided for operation by the drum shaft.

The invention has among its objects to provide a rheostat with readily mountable and demountable resistance units of such construction as to enable compact mounting thereof in a perpendicular relation to the base of the rheostat.

A further object is to provide a readily mountable and demountable resistance unit having supporting parts to directly engage its terminals, one of said supporting parts providing a terminal extension for said unit.

Other objects will hereinafter appear.

One embodiment of the invention is illustrated in the accompanying drawing, in which,

Figure 1 is a fragmentary view, partly in section, of a rheostat and illustrates one resistance unit and the supporting means therefor. Fig. 2 is a plan view of the rheostat with a diagrammatic showing of circuit connections for the resistance units.

Referring to the drawing, the rheostat includes an insulating panel or base A to which are attached in a perpendicular relation resistance units R, one of which is shown in detail in Fig. 1. Each resistance includes a tubular body portion 10 of porcelain or other insulating material having brass caps 11 and 12 spun upon its respective ends and projecting slightly therebeyond. A resistance element 13 is coiled about the body 10 and has its ends connected by soldering or otherwise to the respective caps 11 and 12, the entire resistance being surrounded by a cementitious covering. The projecting inner end of the cap 11 is contracted into an annulus 14C concentric with the body 10, thus forming also a shoulder 15. The cap 11 is so formed as to fit into and abut atubular member 16 which is socketed in the base A while a bolt 17 extending through tubular resistance unit l() serves to secure said unit in position on said base. The tubular member 16, besides serving as a socket for cap 1l of the resistance unit, also serves as a fixed circuit terminal therefor. As shown, the member 16 is connected by conductor 18 to the stud 1S) of a contact 2O on the face of base A. Bolt 17, on the other hand, engages the outer terminal 1:2 of the resistance unit and serves as an extension therefrom to a fixed terminal 21 on the face of base A, said terminal being in' electrical connection with a contact 22. This bolt has a head 23 bearing against terminal 21 and extends rearwardly through the base and resistance unit, being insured adequate clearance with the other terminal parts of the resistance unit by its location in the axial bore of said unit. rl`he outer end of the bolt is threaded to receive a nut 24 to secure the parts together. Obviously the above described unit may be easily and quickly mounted and demounted. Removal of the single nut 24 frees the unit for withdrawal without regard to circuit connections.

The panel A, as shown in Fig. 2, is provided with outer and inner series of contact buttons 20 and 22 arranged in concentric arcs and in staggered relation for progressive engagement by a contactor C which is mounted upon a pivot P for movement in opposite directions from its neutral position, illustrated.

The resistance units, which are illustrated by dotted lines to show the position thereof, and also diagrammatically to facilitate illustration of their electric connections are each connected between a pair of adjacent buttons 22. More specifically, corresponding buttons 22 on opposite sides of the contactor are connected by conducting strips or bars 21, the resistance units being connected b v the supporting bolts 17 to these bars. As shown, there are two resistance units connected to each bar, and as shown in dotted lines, the units may be arranged very compactly upon the panel by staggering thereof. The contacts 20 are similarly connected in pairs but merely by wire connections 18 and each of the resistance units has its free terminal connected as heretofore described to. one of the buttons 22. In this figure these connections are illustrated diagrammatically and from the connections illustrated it will be observed that' a circuit may be traced through the resistance units in series between points X and Y. Hence if it be assumed that the contacter has a line connection, it will be apparent that said contacter when moved in either direction from neutral position will progressively short circuit the several resistance units, and upon reverse movement will progressively open the shortcircuit established thereby.

It will thus be readily-apparent that a rheostat constructed as above described may be easily and readily assembled and wired. The resistance units thereoimay further- -more be very compactly arranged while being at all times readily accessible for removal and replacement.

What I claim as new and desire to secure b v Letters Patent is:

1. In a rheostat, in combination, a base, a circuit terminal therein, a tubular resistance unit having a` terminal to lit said circuit terminal and a bolt extending axially through said resistance unit to demountably secure the same to said base and in contact with said circuit terminal.

2. In a rheostat, .in combination, a base, a circuit terminal therein, a tubular resistance unit having a terminal to it said circuitterminal and a bolt extending axially through said resistance unit to demountably secure the same to said base and in contact with said circuit terminal, said bolt being connected to the opposite terminal of said unit to serve as an extension therefor.

3. In a rheostat, in combination, a base, a bolt fixed to and projecting from said base, a circuit terminal fixed to said base and a tubular resistance unit removably mounted on said bolt and having a terminal to engage said circuit terminal.

In a rheostat, in combination, a base, two circuit terminals thereon, one having an extension, and a tubular resistance unit removably mounted on said terminal eXtens ion, said unit having a 'terminal to be connected to said extension and. a second terminal to engage the remaining circuit terminal on said base.

5. In a rheostat, in combination, a base, a circuit terminal thereon having an eXtension, a tubular resistance unit removably mounted on said terminal extension and electrically connected thereto, and means at the outer end of said unit to releasably secure the same on said extension.

In a rheostat, in combination, a base, a circuit terminal thereon having an extension, a second circuit terminal on Said base, a tubular resistance unit removably mounted on said terminal extension and electrically connected thereto, said unit having a terminal to engage said second circuit terminal and means operable from the outer end of said unit to releasably secure Vthe same on said extension. I

7. In a rheostat, in combination, a base, a circuit terminal thereon having an eXtension, a tubular resistance unit removably mounted on said extension, and electrically connected thereto, a second circuit terminal on said base including a socket, said unit having` a iianged terminal for electrically engaging said socket, and means operable from the outer end of said unit to releasably secure the same on said extension.

S. In a rheostat, in combination, a base, a circuit terminal thereon having an eXtension, a tubular resistance unit removably mounted on said extension and electrically connected thereto, a second circuit terminal on said base including a socket surrounding said extension but spaced therefrom said unit having a flanged annular terminal spaced from said terminal extension for mechanically and electrically engaging said socket, and a nut threaded upon the outer end of said terminal extension for releasably retaining said unit thereupon.

9. In a rheostat, in combination, a base, a circuit terminal socket thereon, a tubular resistance unit having a flanged annular terminal engaging said socket, a second terminal on said unit, a second circuit terminal on said base having an extension projecting in spaced relation through said socket and said unit for electrically engaging said second terminal of the latter, and means on the outer end of said extension for maintaining said unit in releasable engagement thereon and With said socket.

In Witness whereof, I have hereunto subscribed my name.

LEWIS L. TATUM. 

